Extração e Representação de Conhecimento de Séries Temporais de Demanda de Energia Elétrica Usando TSKR

The opening of the Brazilian market of electricity and competitiveness between companies in the energy sector make the search for useful information and tools that will assist in decision making activities, increase by the concessionaires. An important source of knowledge for these utilities is the time series of energy demand. The identification of behavior patterns and description of events become important for the planning execution, seeking improvements in service quality and financial benefits. This dissertation presents a methodology based on mining and representation tools of time series, in order to extract knowledge that relate series of electricity demand in various substations connected of a electric utility. The method exploits the relationship of duration, coincidence and partial order of events in multi-dimensionals time series. To represent the knowledge is used the language proposed by Mörchen (2005) called Time Series Knowledge Representation (TSKR). We conducted a case study using time series of energy demand of 8 substations interconnected by a ring system, which feeds the metropolitan area of Goiânia-GO, provided by CELG (Companhia Energética de Goiás), responsible for the service of power distribution in the state of Goiás (Brazil). Using the proposed methodology were extracted three levels of knowledge that describe the behavior of the system studied, representing clearly the system dynamics, becoming a tool to assist planning activities

Sistema de produção misto de caprino na região central do estado do Rio Grande do Norte

This study aimed to evaluate the performance and profitability of Canindé goats kept under semi-intensive management in mix farming system. 84 animals were used, being 81 does e three bucks.. The means of fertility rate at parturition, prolificacy and percentages of pregnant, kid survival and reproductive rate were compared by Tukey test at significance level of 5.0%. The kid weights from birth to weaning were submitted to variance analysis considering sex and birth type and the means were compared by Tukey test at 5.0% of significance. The percentages of fertility rate by ultrassographic were 91.36 and parturition 74.84. The prolificacy was 1.53. Independently of sex the mortality rate of kids from birth to weaning was 12.3. The average weights of offspring were 2.11 and 1.92 kg and 6.74 and 6.84 kg for male and female offspring at birth and weaning, in this order. The average weights of kids, meaning PN, P28, P56, P63, in the first season of kidding were 2.11 ± 0.46 kg, 3.63 ± 1.04 kg, 5.96 ± 158 kg and 6.74 ± 1.79 kg. There was significant differences (P<0,05) only to birth weight of kids sons of buck 135. However, the fertility at parturition for first and second breeding seasons (BS) were 87.65 and 62.96, respectively (P<0.05). The prolificacy was 1.58 and 1.47 to first and second BS in this order. The percentages of offspring survival from birth to weaning, to first and second BS were 92.86 and 80.00, respectively. From the first BS the reproduction rate was 1.28 while in the second was 0.74. After weaning the duration of lactation was 104 days to first breeding parturition and 38 days in the second one. The total milk production was 853.50 kg. The kids weight gain was influenced by season of year, wet and dry and buck (P<0.05). Were concluded that the seasons of year when breeding season and parturition occur strongly affected the productive performance and profitability of production system

Continuous-time and discrete-time sliding mode control accomplished using a computer

A computer-based sliding mode control (SMC) is analysed. The control law is accomplished using a computer and A/D and D/A converters. Two SMC designs are presented. The first one is a continuous-time conventional SMC design, with a variable structure law, which does not take into consideration the sampling period. The second one is a discrete-time SMC design, with a smooth sliding law, which does not have a structure variable and takes into consideration the sampling period. Both techniques are applied to control an inverted pendulum system. The performance of both the continuous-time and discrete-time controllers are compared. Simulations and experimental results are shown and the effectiveness of the proposed techniques is analysed.

Force and displacement transmissibility of a nonlinear isolator with high-static-low-dynamic-stiffness

Engineers often face the challenge of reducing the level of vibrations experienced by a given payload or those transmitted to the support structure to which a vibrating source is attached. In order to increase the range over which vibrations are isolated, soft mounts are often used in practice. The drawback of this approach is the static displacement may be too large for reasons of available space for example. Ideally, a vibration isolator should have a high-static stiffness, to withstand static loads without too large a displacement, and at the same time, a low dynamic stiffness so that the natural frequency of the system is as low as possible which will result in an increased isolation region. These two effects are mutually exclusive in linear isolators but can be overcome if properly configured nonlinear isolators are used. This paper is concerned with the characterisation of such a nonlinear isolator comprising three springs, two of which are configured to reduce the dynamic stiffness of the isolator. The dynamic behaviour of the isolator supporting a lumped mass is investigated using force and displacement transmissibility, which are derived by modelling the dynamic system as a single-degree-of-freedom system. This results in the system dynamics being approximately described by the Duffing equation. For a linear isolator, the dynamics of the system are the same regardless if the source of the excitation is a harmonic force acting on the payload (force transmissibility) or a harmonic motion of the base (displacement transmissibility) on which the payload is mounted. In this paper these two expressions are compared for the nonlinear isolator and it is shown that they differ. A particular feature of the displacement transmissibility is that the response is unbounded at the nonlinear resonance frequency unless the damping in the isolator is greater than some threshold value, which is not the case for force transmissibility. An explanation for this is offered in the paper. (C) 2011 Elsevier Ltd. All rights reserved.

Controlador adaptativo backstepping a estrutura variavel com Observadores de estado

This research aims at developing a variable structure adaptive backstepping controller (VS-ABC) by using state observers for SISO (Single Input Single Output), linear and time invariant systems with relative degree one. Therefore, the lters were replaced by a Luenberger Adaptive Observer and the control algorithm uses switching laws. The presented simulations compare the controller performance, considering when the state variables are estimated by an observer, with the case that the variables are available for measurement. Even with numerous performance advantages, adaptive backstepping controllers still have very complex algorithms, especially when the system state variables are not measured, since the use of lters on the plant input and output is not something trivial. As an attempt to make the controller design more intuitive, an adaptive observer as an alternative to commonly used K lters can be used. Furthermore, since the states variables are considered known, the controller has a reduction on the dependence of the unknown plant parameters on the design. Also, switching laws could be used in the controller instead of the traditional integral adaptive laws because they improve the system transient performance and increase the robustness against external disturbances in the plant input

Características de carcaça, componentes corporais e rendimento de cortes de cordeiros confinados recebendo dieta com própolis ou monensina sódica

Objetivou-se avaliar os efeitos dos aditivos própolis verde, própolis marrom e monensina sódica sobre as características de carcaça, avaliadas por ultra-som e pós-abate, os componentes corporais e o rendimento de cortes de cordeiros terminados em confinamento. Foram utilizados 32 cordeiros machos, com oito animais por tratamento, mantidos em confinamento por 64 dias. Os animais receberam dieta com relação volumoso:concentrado de 50:50, à base de feno de capim-tifton 85 (Cynodon spp.) e concentrado comercial. O delineamento experimental foi o de blocos ao acaso, com oito animais por dieta, distribuídos aleatoriamente de acordo com o peso: controle, dieta sem aditivo, própolis verde, própolis marrom e monensina sódica. Os rendimentos de carcaça (verdadeiro, quente e comercial) não diferiram entre os aditivos, com médias de 54,97; 44,89 e 41,81%, respectivamente. Os componentes corporais e rendimento de cortes comerciais não foram influenciados pelos aditivos utilizados nas dietas. A metodologia utilizada na determinação teve efeito nas medidas de área de olho-de-lombo (AOL) e espessura de gordura subcutânea (EGS), de modo que, pelo método tradicional, com medidas na carcaça, foram obtidas as maiores médias para AOL (12,14 vs. 9,08 cm²) e as menores para EGS (2,42 vs. 2,69 mm). A correlação entre as medidas de área de olho-de-lombo (AOL) da carcaça e aquelas obtidas por ultra-sonografia foi de 0,8597. Os aditivos não influenciaram as características de carcaça, os componentes corporais e o rendimento de cortes de ovinos terminados em confinamento. A realização de medidas ultra-sonográficas de AOL e marmoreio pode ser utilizada na avaliação de carcaça in vivo em ovinos.

The strands of the F ring disturbed by its closest satellites

Some Voyager images showed that the F ring of Saturn is composed of at least four separate, non-intersecting, strands covering about 45 degrees in longitude. According to Murray et al. [Murray, C.D., Gordon, M., Giuliatti Winter, S.M. Unraveling the strands of Saturn's F ring. Icarus 129, 304, 1997.] this structure may be caused by undetected satellites embedded in the gaps.Due to precession, the satellites Prometheus and Pandora and the ring particles can experience periodic close encounters. Giuliatti Winter et al. [Giuliatti Winter, S.M, Murray, C.D., Gordon, M. Perturbations to Saturn's F-ring strands at their closest approach to Prometheus. Plan. Space Sciences, 48, 817, 2000.] analysed the behaviour of these four strands at closest approach with the satellite Prometheus. Their work suggests that Prometheus can induce the ring particles to scatter in the direction of the planet, thus increasing the population of small bodies in this region.In this work we analysed the effects of Prometheus on the radial structure of Saturn's F ring during the Voyager and early Cassini epochs. Our results show that at Voyager epoch Prometheus, and also Pandora, had a negligible influence in the strands. However, during the Cassini encounter Prometheus could affect the strands significantly, scattering particles of the inner strand in the direction of the planet. This process can contribute to the replenishment of material in the region between the F ring and the A ring, where two rings have recently been discovered [Porco, C. et al. Cassini imaging science. Initial results on Saturn's rings and small Satellites. Science, 307, 1226, 2005].We also analyse the behaviour of undetected satellites under the effects of these two satellites by computing the Lyapunov Characteristic Exponent. Our results show that these satellites have a chaotic behaviour which leads to a much more complex scenario. The new satellite S/2004 S6 also presents a chaotic behaviour with can alter the dynamic of the system, since this satellite crosses the orbit of the strands. (C) 2006 COSPAR. Published by Elsevier Ltd. All rights reserved.

Experimental analysis of the effect of the structure area on the PZT-based SHM systems

The structural health monitoring (SHM) systems based on electromechanical (E/M) impedance technique have been widely investigated. Although many studies indicate the reliability of this technique, some practical considerations still have to be considered in real applications. This paper presents an experimental analysis of the effect of the structure area on the system's performance. The results indicate that the sensitivity of the system to detect damage decreases significantly when the host structure has large cross-section area. Copyright © 2009 by ASME.

On the Chaotic Suppression of Both Ideal and Non-ideal Duffing Based Vibrating Systems, Using a Magnetorheological Damper

In this paper the dynamics of the ideal and non-ideal Duffing oscillator with chaotic behavior is considered. In order to suppress the chaotic behavior and to control the system, a control signal is introduced in the system dynamics. The control strategy involves the application of two control signals, a nonlinear feedforward control to maintain the controlled system in a periodic orbit, obtained by the harmonic balance method, and a state feedback control, obtained by the state dependent Riccati equation, to bring the system trajectory into the desired periodic orbit. Additionally, the control strategy includes an active magnetorheological damper to actuate on the system. The control force of the damper is a function of the electric current applied in the coil of the damper, that is based on the force given by the controller and on the velocity of the damper piston displacement. Numerical simulations demonstrate the effectiveness of the control strategy in leading the system from any initial condition to a desired orbit, and considering the mathematical model of the damper (MR), it was possible to control the force of the shock absorber (MR), by controlling the applied electric current in the coils of the damper. © 2012 Foundation for Scientific Research and Technological Innovation.

Análise do comportamento de um grupo de indicadores de desempenho em uma empresa do setor metal-mecânico

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Crescimento muscular e qualidade da carne de bovinos nelore, simental e seus mestiços no sistema de produção superprecoce

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Controle térmico de componentes eletrônicos com tubos de calor

Pós-graduação em Engenharia Mecânica - FEG

Controle Fuzzy aplicado à melhoria da estabilidade dinâmica em sistemas elétricos de potência

Este trabalho propõe uma estratégia fuzzy, do tipo Rede de Controladores Locais, aplicável à melhoria da estabilidade dinâmica em sistemas elétricos de potência, visando compensar possíveis perdas de sintonia devido à ocorrência de variações nas condições operacionais da planta. A adaptação dos ganhos do controlador fuzzy é efetuada on-line, interpolando-se os ganhos de um conjunto finito de controladores locais fixos. Ao ocorrer variações nas condições operacionais da planta, os ganhos da lei de controle são ajustados automaticamente de modo a manter satisfatório o desempenho do sistema de controle. O desempenho do controle foi avaliado através de estudos de simulação, utilizando-se um modelo dinâmico não-linear, do tipo máquina barra infinita. Os resultados mostram que o emprego da estratégia proposta permite obter melhorias no desempenho dinâmico do sistema.

Análise socioeconômica dos sistemas de uso de terra por pequenos produtores agrários na Amazônia oriental

O objetivo deste artigo é observar a dinâmica dos sistemas de uso agrícola por pequenos proprietários de terra ao nordeste do estado do Pará. No intuito de relacionar formas específicas de agricultura itinerante e de indústria extrativa na Amazônia com os processos endógenos de tomada de decisão econômica. Teve repercussão sobre a dinâmica destes sistemas e as políticas governamentais que a partir de 1970 voltaram-se para a modernização agrícola e a criação de lavouras permanentes, contribuindo para que fossem atingidas barreiras agroecológicos e agroeconômicas. Com base nessas novas dinâmicas, os pequenos empreendimentos familiares na Amazônia defrontam-se com ações públicas e privadas que fragilizam essa estabilidade.

Avaliação da suplementação alimentar com bactéria probiótica no crescimento e sanidade de Arapaima gigas em sistema de recirculação de água

As bactérias acido lácticas tem se destacado por desempenhar efeitos benéficos ao hospedeiro, entre eles destacam-se a ativação no sistema imunológico, desempenho zootécnico e eficiência alimentar. O objetivo deste trabalho foi selecionar e a avaliar bactérias potencialmente probiótica no crescimento e sanidade de Arapaima gigas. A primeira etapa foi o isolamento e seleção de bactérias com potencial probiótico a partir de 10 juvenis de A. gigas sendo submetidas a testes in vitro de inibição de patógenos bacterianos conhecidos para aquicultura, e a segunda etapa consistiu em testes in vivo avaliando a colonização do trato intestinal pela cepa bacteriana e sua relação com a hematologia. A cepa com melhor halo de inibição foi identificada com o kit API50 CH como Lactobacillus paracasei (99.9%). Para avaliação in vivo, os animais foram alimentados durante 120 dias com dieta contendo somente leite estéril (T1), dieta controle sem bactéria (T2), dieta com 105 L. paracasei (T3) e dieta com 106 L. paracasei(T4). Após este período os peixes foram submetidos três tratamentos: injeção intraperitoneal com Aeromonas hydrophila, injeção de solução salina e peixes não injetados. Ao final de 24 horas de desafio foi observado elevada mortalidade dos peixes pertencentes ao grupo T3, T4 em relação ao T1. Os resultados nos permite concluir que a cepa utilizada nos testes in vivo não influenciou o desempenho zootécnico, além de ser ineficaz na proteção contra a infecção por Aeromonas.